Focused on issues of drug treatment in relation to autism. Pharmacological treatment studies in autism are complicated by various factors including a tremendous range of syndrome expression, a lack of robust animal models of the disorder, and various methodological problems. Theories have tended to follow treatments, and various neurochemical systems have been the focus of study. Neurochemical systems potentially implicated include those involving dopamine, norepinephrine, serotonin, and neuropeptides. The dopaminergic system has been the most extensively studied. Treatments developed are effective relative to certain disabling symptoms but "core" problems (e.g., in social relatedness and communication) appear less responsive to medications. The development of new approaches to assessment, including integration of behavioral and pharmacological approaches, is an important research priority.